CN106457826A - Sturdy drop generator - Google Patents

Abstract

The invention discloses a sturdy drop generator. The invention relates to a device for forming and ejecting drops of an inkjet of a CIJ printing machine, said device comprising: a) a cavity for containing an ink and comprising an end provided with a nozzle (10) for ejecting drops of ink, and b) actuator means (21, 22, 32, 41, 42) in contact with the cavity. The invention relates to a device wherein the jet velocity modulation from the nozzle (10) has a value of [Delta]Vj(ft) at the operating frequency, and does not vary, at a temperature equal to 15 DEG C and to 35 DEG C, in a frequency range of +5 kHz around the operating frequency ft, outside the range between 0.25[Delta]Vj(ft) and 4 [Delta]Vj(ft). In order to achieve this, the acoustic impedance of the cavity is suitable for limiting the influence thereof on the jet velocity modulation.

Description

Strong droplet generator

Technical field

The present invention relates to the improvement of the operation of printhead of continuous inkjet (CIJ, continue ink jet) printer with Make it strongr towards the environmental change (especially temperature) set up on the industrial application of the type printer.

This improvement involves the incentive functions of droplet generator towards the raising on the robustness of temperature.

Background technology

Continuous inkjet (CIJ, continue ink jet) printer is in the coding for various products and industrial label example As known in directly on a production line and with two-forty field of joint strip code or deadline on food product be.Such Type printer also establishes the application in graphics area, wherein develops the probability of the graphic printing of this technology.

CIJ printer constantly generates droplet jet, and some of them droplet jet is selected and is directed to and waits to be printed Support member, and other droplet jets be recovered as reuse.These printers have the sub-component of some standards, such as Fig. 1 Shown.

First, printhead 1 (typically deviating from the main body of printer 3) is connected to by flexible line (umbilical) 2 The main body of printer 3, this flexible line 2 will promote to carry out integrated motility on a production line and right by providing to printhead Fluid power needed for printhead is operated is engaged with electrical connection.

The main body (also referred to as control station or rack) of printer 3 generally comprises three sub-components：

The line of ink marker road 4 at section below (the region 4 ') place of-control station, its main purpose be on the one hand with stable pressure and With suitable quality, ink is provided to printhead, and on the other hand accommodate the ink-jet not being used for printing；

The controller 5 at-control station upper section (region 5 ') place, can manage action sequence and execute process to enable Printhead to be activated and line of ink marker road difference in functionality；

- interface 6, interface 6 is used for realizing printer and the means for notifying its operation based on operator.

This description goes for referred to as binary dump machine or the continuous inkjet (CIJ) deflecting continuous jet printer more Printer.

Binary system continuous inkjet printers are equipped with printhead, and the droplet generator of printhead has a large amount of injections, spray The drop penetrated can only be directed to 2 paths：Print path or reclaim path.

Deflect in continuous jet printer, each liquid of single injection (or the injection opened with several injection intervals) more Drip and can be deflected on various paths corresponding with different command.The a series of drops of experience different command therefore can be along Scan region to be printed as the direction of yawing moment, wait that another scanning direction in the region being printed by printhead and is treated The relative movement of the supporting member 8 being printed covers.In general, these elements are arranged such that this both direction substantially Vertically.

The continuous inkjet printhead deviateing has different operation sub-assemblies.Fig. 2 especially depicts many deflection continuous inkjets The printhead of printer.Printhead includes：

- for generating the device 10,63 of droplet jet, referred to as droplet generator or excitation main body；

- for reclaiming the device 62 of the ink not being used for printing；

Device 65 for the drop for printing for the deflection；

For monitoring and controlling the device of drop deflection process (synchronization of droplet formation and deflection command).

With reference to depicting Fig. 2 deflecting continuous inkjet printhead, there is droplet generator 60 more, in droplet generator 60, Chamber is provided with conductive ink.This ink under stress is kept to pass through at least one by the line of ink marker road 4 being normally at outside printhead Measure nozzle 10 and flee from this chamber, therefore form at least one ink-jet 7.

Periodic excitement device 63 be associated with chamber and nozzle 10 black contacts upstream；Periodic excitement device 63 will periodically be adjusted System is sent to ink, periodically modulates the modulation causing speed and radius of spray from nozzle.When the size of these elements is suitable, Under the influence of the surface tension (up to injection is split) of the capillary instability of responsible injection, this is modulated at and amplifies in injection. This splits is regularly and the accurate distance that results from away from nozzle so-called " rupture " of being in away from injection is put at 13, this distance Depend on excitation energy.

In the case of the excitation set of referred to as executor, its movement parts is piezoelectric ceramics, the ink with the chamber upstream of nozzle Contact, excitation energy is directly related with the amplitude of the signal of telecommunication for driving piezoelectric ceramics.The other sprays of teaching in prior art Penetrate exciting bank (heat, electrohydrodynamicss, acoustics ...), but the efficiency due to piezoelectric ceramics and relative ability to work, Excitation using piezoelectric ceramics is always most common.

At its breakdown point 13, from nozzle, continuous injection was changed into identical and the black liquid being evenly spaced apart originally The string 11 dripping.Temporal frequency according to the excitation energy with the frequency identical of pumping signal and for being given forms drop, appoints What other specification stablize (especially black speed) otherwise, periodic excitement signal and this as regularly and with sharp Encourage and between the frequency identical moment of rupture of signal, there is accurate (constant) phase relation.In other words, the week of pumping signal The precise moments of phase correspond to the precise moments on the separation power of injection drop.

In the case of there is no further action (this be drop be not used for print situation), clusters of droplets along with liquid Drip ejection shaft (the nominal path of injection) conllinear path 7 advance, drop ejection shaft by the geometric construction of printhead with time Receive groove 62 to engage.This is used for reclaiming the ink that groove 62 undertaking of unprinted drop is not used by, and the ink being not used by returns to the line of ink marker Road 4 is to be recycled.

For printing, drop is deflected and deviates the nominal path 7 of injection.Thus, they are fled from groove and following and incline Ramp line 9, tilts path 9 and encounters, at different expectation rum points, the support member 8 waiting to be printed.All these tracks are all same In one plane.The placement of the drop on droplet impact matrix on support member to be printed on e.g. is passed through such as with forming character Get off realization：Will be (typically vertical with printhead and supporting member to be printed for the individual deflection of the drop on printhead deflection plane Straight in deflection plane) between relative movement combine.In the continuous jet printing technology deviateing, deflection is by drop Charge and by drop is transferred to what electric field was realized.In practice, the means for making drop deflection are included for every The single charging electrode 64 of individual injection, charging electrode 64 is located at the vicinity of the breakdown point 13 of injection.It is intended to predetermined charging Value each drop being formed optionally is charged it is however generally that, drop charge value each other is different.In doing so, ink It is maintained at fixed potential in droplet generator 60, charging is applied in by the voltage groove with determination value that control signal drives Electrode 64, this value is different in each groove cycle.

In the control signal of charging electrode, voltage is engraved in injection classification (franctionation) when applying be short before Temporary attracts the given quantity of electric charge with using the advantage of injection electric continuity and spraying at point, and the given quantity of electric charge is voltage The function of value.The charge-variable voltage of this offer deflection is typically between 9 and 300 volts.Then this voltage is during being classified Maintain so that charge stable, till separate drop is electrically insulated.Afterwards, voltage still keeps applying certain time, will Moment of rupture problem is taken into account.

Therefore, attempt making voltage apply moment and injection classification process synchronization.In the case of desynchronizing, liquid of interest Drip and be not appropriately charged, its voltage is low or even zero.

Drop deflection device is additionally included in one group 2 deflections place on the either side of drop path upstream of charging electrode Plate 65.This two deflecting plates are placed to the relative potentials of high fixation, result from the substantially vertical electric field Ed of drop path, electricity Field Ed can make attraction charged droplets deflection between two plates.Deflection amplitude is electric charge, quality and the speed of these drops Function.

In order to control the deflection for the drop printing, attempt in the scope of the change of the environmental condition that specification is provided Produce quality rupture.

Thus, attempt to ensure that：

On the one hand, in the field of charging electrode, therefore away from nozzle really set a distance (rupture location) place set up rupture；

And, on the other hand, stablize and it is contemplated that carry out injection rupture (rupture quality：Rupture matter will be provided below Amount).This logical over excited optimal setting to be carried out, by acting as excitation energy for encouraging in wherein putting into practice. In prior art in most cases, come by the horizontal Vs in the periodic voltage signal being applied to activator (piezoelectric part) Control excitation energy.

When rupture makes especially by for giving black temperature range (black speed is had an impact) come the printer to characterize Opereating specification in ensure that drop optimal charge when, rupture is considered as stable and reliable (having good quality).

Specifically, just before rupture, drop is connected to the drop (referring to Fig. 3 A) followed being formed by afterbody.This tail The shape in portion determines rupture quality.The shape having feature most of problematic rupture be following shape (but there may be perhaps Many more or less stable intermediate case)：

(surface tension cohesive strength is with respect to quiet for the risky very thin afterbody (referring to Fig. 3 B) being ruptured astatically Electric power and step-down).(the low electricity when there is very high electric field between in succession two drops charging with very different value Lotus follows the situation of forceful electric power lotus), create electrostatic force in the point effect phenomenon of afterbody and make charged particle from the drop of soaking Very thin afterbody tearing goes out and adds low electric charge drop by transmitting electric charge.Thus, it is nominally electric that drop no longer has it Lotus, therefore deflection multilated and print quality reduce.

There is between two choke valves the afterbody (referring to Fig. 3 C) of sliver (lobe), this afterbody can be broken two Insulation satellite that is individual local and creating drop, insulation satellite takes a part for the electric charge being intended to drop of concern away.

If * the speed of this satellite ratio sprays fast (quick satellite), this satellite and its electric charge will add liquid of concern Drip and re-start nominal situation without having undesirable effect to print quality；

If * satellite velocities with injection speed identical (unlimited satellite) or be added without this liquid before the deflection of satellite Drip, then violence is deflected by this poor and satellite of charging, has the risk of obstruction printhead；

If * satellite adds subsequent drop (slow satellite), the electric charge of drop of concern is transferred to subsequently by satellite Drop and upset deflection.

In addition to black rheological behavior, black shape is also related to stimulation level (excitation density).Fracture pattern determines Rupture quality is it is ensured that be the ability of fracture pattern to the suitable charging of drop.

In general, when excitation increases, rupture is modified to after satellite rupture switches to enter no satellite rupture. Satellite is defined as the subsidiary fracture of the rupture from main droplet.

By increasing stimulation level further, rupture returns in satellite system.Meanwhile, with respect to the rupture position position of nozzle Changed by following the curve of Fig. 4.

The curve of Fig. 4 be denoted as driving voltage VS (Lb=f (VS)) function, be given nozzle 10 and breakdown point 13 it Between rupture distance (Lb) characteristic f profile.This curve will be referred to as encouraging curve below.This is to be swashed by scanning and excitation Generate electricity and press the value of VS and by determining what the Lb being used for each VS value set.

When excitation excites increase (increase from low value), nozzle/rupture of starting from high level (naturally injection rupture) away from Reduce and through minima (referred to as " flex point ") from (Lb), then extend again.The shape of this curve and physical location depend on In many parameters, especially black attribute and temperature.Although printhead is designed so that the transmutability that refer in parameter but should The function part of curve still builds in the field of charging electrode at least in part.On the other hand, it is present in rupture quality correlation Function area, wherein printing is gratifying (charging of drop is suitable).The region being properly located in electrode and rupture The intersection of the function area of quality is corresponding to the operable scope of excitation.This excitation range is by the input point (Pe) on the left side and the right Output point (Ps) characterizing, as indicated in fig. 4 as.If the use condition of tape/tube printer is not how, excitation is operable Scope is all sufficiently good limited, then excitation system will be gratifying.

At least two distinct operator schemes for piezoelectric excitation are used in the ink-jet printer of prior art： This two operator schemes are resonant excitation mode and non-resonant excitation pattern.

Non-resonant excitation is relatively difficult to realize and require very big energy because executor must be provided for create with Whole energy needed for the displacement of executor's part of ink contact are to generate the pressure modulation upstream of nozzle.On the other hand, should Pattern encourages the variability of condition relative to tolerable.

By contrast, resonant excitation has the periodic excitation of the periodicity rupture in the droplet jet leading to fixed frequency In the range of produce much more advantage, this in continuous jet-type Method of printing be often this situation.In fact, at this In the case of, highly effective rate is the oscillating or vibrating system that executor is designed as substantially being tuned to drop emission frequency； Then, low periodicity excites the standing wave that can remain amplified, and amplified standing wave will generate the pressure modulation upstream institute of nozzle The displacement amplitude needing.

Under the conditions of the realization that can sense, single piezoelectric ceramics is (for, in pattern D33, depositing on ceramics two The electric field creating between electrode has therefore produced longitudinal stretching or contraction, and longitudinal stretching or contraction are plan direction and the signal of telecommunication The function of polarity) executor cannot be itself served as, because single piezoelectric ceramics will not have for creating desired ink ejection speed The abundant deformation amplitude (only one nanometer of the moon) of degree modulation；Therefore, it is fixed in the part for being amplified to movement, referred to as Resonator.Pottery/resonator assembly is referred to as executor.

May have noticed, some ink for droplet generator and size, launching efficiency is not intended as temperature Function and stablize.

This may or even cannot be under at least 15 DEG C or 20 DEG C some exact temperature and/or under some temperature ranges (especially at 5 DEG C or at 15 DEG C, and at 35 DEG C and/or at 45 DEG C (and/or 50 DEG C)) and/or in these different values two Between two, (especially between 15 DEG C and 35 DEG C or between 5 DEG C and 45 DEG C (or even at 50 DEG C)) are carried out to printer Operation.

In fact, in some conditions, excitation becomes entirely without efficiency and operable excitation range is mobile and/or weak Change, disappear in some cases, this makes it impossible to carry out machine setting.

In some cases, can attempt being adjusted according to predictable temperature range in the production phase using printer Excitation setting.But this is not feasible all the time.

Finally if it is desired to compensate this unstability it is necessary to realize (for example, the temperature control of printhead of further device System), this imposes fringe cost.

Thus, cause the problem finding following apparatus and method：This apparatus and method allows at least 15 DEG C or 20 DEG C At least two different temperatures, especially on the one hand at 5 DEG C (and/or 15 DEG C) on the other hand at 35 DEG C and/or at 45 DEG C And/or at 50 DEG C, preferably in these values between any two, especially between 15 DEG C and 35 DEG C or at 5 DEG C and 45 DEG C Between (or even 50 DEG C), satisfactorily operated.

Another problem is that particularly by the one hand for resonator in the system realizing resonant mechanical executor The velocity of sound in material (for example, rustless steel) and on the other hand fluid in the velocity of sound (in resonator, be about 5000m/s, fluid In be about 1250m/s) be about 4 ratio the fact that and executor's resonance and fluid resonance are coupled, the velocity of sound in fluid It is about a quarter of wavelength.The result of this ratio is above-mentioned coupling.

Content of the invention

It is an object of the invention to solving these problems.

According to the present invention, the equipment of the ink-jet drop for being formed and launching continuous inkjet printers device includes：

A) chamber, for accommodating ink, and includes being equipped with the end for launching the nozzle that black liquid is dripped,

B) actuator apparatus, actuator apparatus are contacted with chamber.

In such devices, at the operation frequency in chamber and the operation frequency of executor, the sound in the chamber near nozzle Resistance has value ZT (ft).

Preferably, this acoustic resistance does not change, or changes in the frequency range around operation frequency ft+5Hz a little so that spraying Change in velocity modulation in mouth keep following temperature the one side 0.25 (or 0.5) of velocity modulation and on the other hand 2 (or 4) again：Reference temperature (for example, for 25 DEG C), and away from least 10 DEG C or 20 DEG C of at least 2 positive temperature, especially exist 15 DEG C and at 35 DEG C, preferably also at 5 DEG C, and/or at 10 DEG C and/or at 20 DEG C, further preferably at 45 DEG C or even At 50 DEG C, further preferably in the temperature comprising at least to be spaced [15 DEG C -35 DEG C] or be even at least spaced [5 DEG C -50 DEG C] Any temperature in scope.

The resonance being led to due to black chamber according to such equipment of the present invention and anti-resonance frequency can displacement so that making For the function of temperature its drift in following temperature do not make they with injection driving frequency intersect：At least 15 DEG C and 30 DEG C (or At 35 DEG C), preferably at 5 DEG C and/or at 10 DEG C and/or at 20 DEG C, further preferably at 45 DEG C or even 50 DEG C, enter One step is preferably in the scope between 15 DEG C and 35 DEG C and the more generally any temperature in the scope between 5 DEG C and 50 DEG C Degree.The temperature range of the operations specifications of these temperature and/or the actually many printers of temperature range.

Preferably, described chamber be so that the length of mechanical actuator and be intended to accommodate fluid column chamber this part or The ratio of partial length is higher than strictly 4；This ratio can be for example between 4 and 6 or between 4 and 10 or 100.

According to first embodiment, the interior shape in chamber can include：

First cylindrical region, the first cylindrical region has the first diameter and the first length of the longitudinal axis measurement along described chamber Degree,

Second cylindrical region, the second cylindrical region has different from the Second bobbin diameter of the first diameter with along described chamber Second length of longitudinal axis measurement.

Therefore, create the interval chamber of at least two cylinders of different-diameter, so that for the common black velocity of sound The black chamber frequency mode of oneself is subjected to displacement.The cylinder interval of different-diameter makes it possible to make the change in fluid length.

Actuator apparatus (for example, piezoelectric ceramics) can be with the internal capacity directly contact in chamber.

Actuator apparatus can include resonator element.Executor is thus resonance.

According to an embodiment, this resonator element includes the resonator body being placed in chamber.

According to another embodiment, the wall in chamber forms at least a portion of resonator.

Resonator can be metal or mineral attribute, for example, rustless steel, aluminum, beryllium, pyrite, copper, diamond, glass, Gold, ferrum, lead, TMMA, silver or titanium.

Resonator body can include having the Part I of the first diameter and have second straight different from the first diameter The Part II in footpath.

The invention still further relates to being used for forming and launch the equipment of the drop of ink-jet of continuous inkjet printers device, this equipment Including：

A) chamber, chamber is used for accommodating ink and includes being equipped with the end of nozzle, and nozzle is used for launching black liquid and drips,

B) actuator apparatus, actuator apparatus are contacted with chamber, and the material of actuator apparatus is selected from aluminum, beryllium, pyrite, copper, gold Hard rock, glass, gold, ferrum, lead, TMMA, silver or titanium.

The length in black chamber typically can be comparable with the length of the resonator below flange, and resonator is chosen as allowing executor's Mechanical resonant.

The physical attribute of resonator is adjusted to enable a device in given frequency resonance.

Select material than stainless steel, and the length of bar and the length in black chamber therefore make in ink not Desired resonance and anti-resonance frequency are removed from useful scope (executor's resonance) middle position.

Therefore, such material is selected to make it possible to cancel the liquid accommodating in chamber for Resonator device and lead to Spurious resonance.

Resonator device can include piezoelectric element.

Resonator can be inserted in resonator body, and resonator body has constant or variable the cutting in longitudinal direction Face.

This resonator body can include the Part I with the first diameter and have different from the first diameter second The Part II of diameter.

Two embodiments can be in conjunction with to optimize final implementation.

In any embodiment or two embodiments, according to the present invention for formed and launch drop equipment permissible Accommodate ink, such as wherein ink between 800m/s and 2000m/s for the velocity of sound.

The invention still further relates to the printer device of continuous inkjet (CIJ) type, this machine includes：

- printhead, printhead be equipped with according to one of embodiment described above for being formed and launching The equipment of the drop of ink-jet,

- line of ink marker road,

- for the device that is controlled of circulation to ink and printhead.

The invention still further relates to for forming the method that black liquid is dripped, wherein realize equipment as described above and as described above Machine.

The invention enables resonant excitation principle can be retained with its advantage (efficiency, cost).

Present invention could apply to difference realizes the droplet generator of type.

Two embodiments (there is the chamber of some acoustic impedances, and the certain material being selected for resonator) introduced Combination make it possible to limit each pattern some shortcomings specific；This makes it possible to especially realize between both Compromise：

Gratifying overall space, this be due to overall space relevant with pole length (in addition to other things also according to Rely in the velocity of sound)；

Combine with the complexity in chamber and black printhead space, easily clean chamber.

Brief description

Fig. 1 is the scheme of the structure deviateing continuous jet printer,

Fig. 2 is the scheme of the printhead deviateing continuous jet printer,

Fig. 3 A-3C represents different rupture configurations, and Fig. 3 A represents good quality rupture, and Fig. 3 B is thin afterbody rupture (having the risk from material tearing), and Fig. 3 C be sliver rupture (having satellite risk),

Fig. 4 refers to the curve being shown as encouraging function, rupture distance the time exciting to change,

Fig. 5 A-5E represents the structure of the excitation main body 20,30,40,50 and 60 that can apply the present invention,

Fig. 6 is the curve of launching efficiency, provides the rupture length of the function as injection driving frequency,

Fig. 7 A-7B represents the result that the excitation main body of the type using Fig. 5 D is obtained,

Fig. 8 shows the exemplary model of excitation main body,

Fig. 9 is the electrical analogue of the equivalence of excitation set,

Figure 10 A-10B represents the frequency response of the excitation main body of the black temperature different for two,

Figure 11 represents that other supplement result,

Figure 12 A-C represents the test result being obtained using another type of excitation main body,

The time that Figure 13 A is denoted as in function the, acoustic resistance of frequency changes, and Figure 13 B is denoted as the function of frequency , the time in the modulation of jet velocity change,

Figure 14 A-E represents the structure of the excitation main body realizing the present invention,

Figure 15 A-15C represents the test result being obtained using the excitation main body of the present invention,

Figure 16 have collected ultrasonic velocity data function, being directed to different ink as temperature,

Figure 17 is schematically showing for device that ink-jet printer is controlled.

Specific embodiment

In Fig. 5 A, Fig. 5 B, Fig. 5 C, Fig. 5 D and Fig. 5 E, illustrate for realize present invention can apply to excitation main body 20th, five types of the excitation executor in 30,40.Some of which (Fig. 5 A, Fig. 5 D) includes being intended to be present in when ink It is immersed in the resonator in ink when in chamber.

The excitation main body 20 of Fig. 5 A includes shell 25, the internal capacity of shell 25 preferably have cylindrical shape and along Axle XX ' extends.

Main body 20 further includes executor, and executor includes the pottery 21 of piezoelectric, pottery 21 have along The cylindrical shape of axle XX '.Executor is installed in the shell 25 of modulation main body 20.

This pottery is metallized on two faces 210,212 of axle XX ' at it.This pottery is coaxially fastened to justify Post metallic rod 22.For example, by be fixed with gluing, this glue can be advantageously conducting resinl.

According to shown embodiment, this bar includes annular flange flange 23, and the face 212 of pottery is attached at annular flange flange 23 On.

Shell 25 can be equipped with seat or inner support face 250, and inner support face 250 is vertical with cylindrical axle XX ', and Inner support face 250 is equipped with hole 252, by hole 252, can introduce cylindrical metal bar 22.The bearing-surface 230 of cylindrical lip 23 Therefore can be bearing on inner bearing face 250.

Machinery (not shown) makes flange 23 (therefore executor) occupy center and be clamped down on to surface 250.

The internal capacity of shell 25 is located at below surface 250 and flange, defines insulated cavity 24.

In use, by conduit 26, the ink of pressurization is supplied to chamber.

Nozzle 10 (ink is from nozzle 10 out) is placed on the bottom in chamber 24, and calculates this assembling and make at the end of bar 22 Significant surface (active face) 222 at portion is located at nozzle 10 top and close to nozzle 10 it is preferable that at tens millimeters At distance, such as between 2/10mm and 5/10mm.

Modulation main body inner member (executor, shell 25, nozzle 10) in each be ring section and these Different elements is relative to each other coaxially placed on axle XX '.

For practical reasons, bar 22 is preferably：

(by the processing plasticity) of very big hardness；

Conductive or metallized material, is moved to the no-voltage being applied to ink on one of electrode of pottery 21；

If if it is contacted with ink, being erosion-resisting.

A kind of spendable material is rustless steel, and rustless steel has above-mentioned complete characteristic.

By construction, the supporting surface 27 of flange 23 is corresponding with the vibration nodal point of executor, and this is by transferring the energy to tune Loss in efficiency is avoided in the structure of main body processed.

Moreover it is preferred that be located at nozzle 10 top, bar 22 end 220 benefit from corresponding with vibration antinode Big mobile range.

In practice, executor can be tuned to so that resonance is located at the vicinity of operation frequency (so-called " drop " frequently Rate, or be even intended to generate the frequency of drop), but and inaccurately identical not make the realization to executor for this system Change in condition (for example, the mechanical tolerance to miscellaneous part for the executor) is too sensitive.Typically in atmosphere, with operation frequently The frequency that rate deviates carries out this tuning, and for taking frequency slips into account, frequency slips are located at different materials (example with when bar As ink) in when the resistance difference that exists relevant.

In this example, the part below flange 23 of bar 22 is placed on chamber 24 (main body of droplet generator) In, the length in chamber 24 is substantially identical with the length of bar 22.

In use, the electrode 210 of pottery 21 is connected to electric supply installation 27.Main body 25 can be connected by flange 230 It is connected to and will be moved to the ground 29 of electrode 212.

Fig. 5 B describes the second embodiment of resonant modulation main body 30.

The operation of second embodiment is close to the embodiment describing above in conjunction with Fig. 5 A.

There is chamber 34 again, chamber 34 has cylindrical interior shape, by two end face 320,322 vertical with axle XX ' Limit.By conduit 36, the ink of pressurization is put in this chamber.The first end of this tubular cavity is by the partition wall 322 vertical with axle XX ' To close.Nozzle 10 is formed on the second end partition wall 320 to allow injection to go out along axle XX '.

There is provided the function of being guaranteed by the bar 22 of first embodiment to the shell 32 that chamber 34 is defined.By by mechanical means Or excite this function by the piezoelectric ceramics 31 fixed is adhered on partition wall 322.Pottery-casing assembly forms resonance Device, partition wall 322 is at vibration nodal point, and maximum mobile range is located at and is equipped with the plate 320 of nozzle 10.Therefore, shell Length L be chosen as the vicinity of operation frequency shell 32 strong point create standing wave.In this case, black institute present in chamber The impedance influences brought be taken into account with by this assembly be tuned to suitable frequency.

In use, an electrode of executor's (for activating to pottery 31) is connected to electric supply installation 37.Outward Shell 32 can be connected to ground 39.

Fig. 5 C describes 3rd embodiment, and in the third embodiment, piezoelectric ceramics 41 is ring-type and is placed on tool Have in the throat 48 of annular outer cover 42 of tubular cavity 44.Chamber is closed by partition wall 422 at top, and is equipped with drop bullet The plate 420 penetrating nozzle 10 is located at bottom.Carry out ink supply by conduit 46.

When mounted, pottery 41 is clamped between side 48a and 48b of throat.In electrode, (electrode is arranged to pottery Corona on the face vertical with its axle of element 41) between under the influence of the periodicity electric field that creates, this can longitudinal crust deformation And this vibration is sent to the shell 42 that it is fixed to.This excites and is sent to nozzle 10, is then delivered to spray.As In the embodiment of Fig. 5 B like that, it is that shell is playing the effect of resonator.

In use, executor 41 is connected to electric supply installation 47, and this electrode is electrically insulated with shell 42.Shell 42 can be by It is connected to ground 49.

Fig. 5 D describes fourth embodiment, in fact, fourth embodiment is the replacement reality of first embodiment described above Apply example.Refer to identical or corresponding element with the reference number identical reference number in Fig. 5 A.Reference number 51 and 52 points Do not refer to piezoelectric ceramics resonator.

Different from the structure of Fig. 5 A, from flange 53, resonator 52 includes 3 sections 521,522 with different-diameter With 523：There is the first section 521 slightly than the low diameter of diameter of the port of insertion executor, have lower diameter and Make it possible to limit by the second section 522 of the volume 54 of storage ink, there is diameter that more will be low and terminate ink ribbon being arrived 3rd section 533 of the conduit of nozzle.In fact, being inserted between the diameter of the wall of shell 25 of executor and the first diameter Difference enables ink to circulate, and wherein injects ink by side conduit 26.This actuator types be commonly used in have so-called The drop of " middle " size, and its shape be optimized for by the machinery realized on printhead forced given overall Operating condition (especially operation frequency) in space.In the figure, region A, B, C list notation, this will in the following description Use.

Being partially disposed within chamber (main body of droplet generator) of the bar of flange 53,23 lower section, the length of bar again with The same length of the resonator 52 in chamber 54.

Above in conjunction with Fig. 5 A and especially in combination with those relevant with the operation frequency of the connection and executor of electric supply installation The explanation having been given by is herein defined as applicatory.

Printhead can have following mechanical arrangements：This mechanical arrangements has different size (in order to simplify for generation： High, middle and may be little) if drop, the droplet generator of dry type correspondingly being operated at different frequencies be altogether ?.Therefore, for the generator of all types, overall space and input/output can be identicals；For these inhomogeneities Type, cavity length can also be closely.Retain base in order to different resonator types can operate at different frequencies Length between this identical flange and nozzle, can work to rod-shape.Thus, for the bar (lowest frequency of printhead G Rate) it is simple cylinder, this cylindrical length is highest (for example, Fig. 5 A), and the shape of printhead M (higher frequency) Shape has more complicated shape (two diameters, for example, Fig. 5 D), this make by higher frequency be operable to keep with The substantially the same length of printhead G.

But the spurious resonance that is to be solved, generating in fluid column being given below in this application and especially Identical with the problem holding that the excited coherent of the function as temperature relates to.In the prior art, especially in document JP 2006- In 076039 or JP-2005-081643 or even US5063393 or JP-S58-3874, do not emphasize the parasitism of these resonance Characteristic.

Fig. 5 E represent present invention can apply to another type equipment.With those the reference number identical references in Fig. 5 B Label refers to identical element.

Again, there is chamber 34, chamber 34 has cylindrical interior shape, in that side of nozzle 10 due to the vertical end of axle XX ' Face 320 is limiting chamber 34.By conduit 36, the ink of pressurization is put in this chamber.

The other end of this tubular cavity and executor's directly contact, be here piezoelectric ceramics 31 (piezoelectric ceramics 31 itself by Peripheral flange remains to the wall in chamber).

In the figure, chamber is the elongated shape according to axle XX '.But chamber can also be bending.

In use, the electrode of executor 31 is connected to electric supply installation 37.Shell 32 may be connected to ground 39.

In the device, do not provide, to the shell 32 that chamber 34 is defined, the function of being guaranteed by the bar 22 of first embodiment. Pottery-casing assembly does not form resonator.Ink vibration is directly made by executor 31, and resonance is formed at chamber with operation frequency In.

The equipment of the type and presented hereinbefore those have identical problem, especially for as Fig. 5 A-5D Other equipment.

In general, being directed to the optimal performance frequency to determine injection for the different parameters limiting injection.In these parameters, Exist：

The diameter (this diameter can be between 40 μm and 80 μm) of nozzle,

Jet velocity (jet velocity can be between 18m/s and 24m/s),

The physical-chemical parameters of ink：Surface tension (for example, between 20mN/m and 60mN/m), dynamic speed are (for example, Between 2cps and 10cps), and density (for example, between 800Kg/m3 and 1400Kg/m3).

Operation frequency can be adjusted using the device 27,37,47 for applying a voltage to piezoelectric element.

Driving frequency is represented by function, the rupture length Lb as injection stimulating frequency.

Can be by using camera head with synchronous with drop period (this enables the image of drop to be formed to fix ) stroboscope come to observe injection and measure Lb.Then, nozzle and rupture are measured by the microbit in-migration of camera head Between distance.

When drop is charged with (in constant droplet formation frequency), (especially join in document WO 2012/2107560 See the description of Fig. 5 A-5C with reference to this document) in, or even describe another technology in WO 2011/012641.

Generally speaking it is contemplated that rupture length is lower, launching efficiency is higher.The curve of Fig. 6 is denoted as injection and excites frequency Function, Lb the time of rate changes.The amplitude highest frequency of radius modulation or speed is referred to as spraying resonant frequency.Typically For, adjustment executor frequency near this frequency.In fact, due to injection by its diameter, its from nozzle output speed, And make its fluid (being responsible for the capillary instability of injection by the surface tension of this fluid) upwards to limit, spray table It is now the system of resonance at given advantageous frequency.When Negotiation speed modulation periodically to excite, capillary instability will It is reflected as the cyclically-varying on sprayed fiber concrete, and the cyclically-varying on sprayed fiber concrete will be exaggerated until injection ruptures.Make Length Lb being located at by function, this rupture of stimulating frequency represents the injection resonance for given driving voltage.

According to indicated above those, optimum excitating frequency ν 0 is frequency corresponding with the bare minimum of length Lb.

However, it is possible to the actual curve that function, Lb the time as injection stimulating frequency that have noticed changes (representing its example in Figure 12 A-12C, Figure 12 A-12C will be discussed further below) does not have the ideal form of Fig. 6.This Actual curve shows the upset of the frequency event that the frequency response of reality is attached a bit.

More accurately, may have highlighted that when using any excitation main body, involve three resonator systems：Injection is humorous Shake, executor or resonator resonance, and the resonance of the fluid cavity of droplet generator.In other words, some frequencies have been observed Behavior, these frequency behaviors do not correspond to executor's resonance, do not correspond to injection resonance yet.

Injection unstability to be excited by executor, and this is it is ensured that its incentive functions.Executor preferably by The resonant frequency being designed such as the resonant frequency and executor spraying is relatively close to each other.

In the comparison to this two resonance, the resonance of fluid cavity is spurious resonance.It causes to temperature very in ink The deformation of sensitive standing wave.This standing wave becomes to be added to executor and excites.

For so-called " resonance " executor series, the resonant frequency of executor depends on the sound in the material of resonator rod The speed of ripple and the size of resonator rod.In the case of the structure of Fig. 5 A, the length of resonator is to make at resonant frequency There is the antinode keeping vibration nodal point and end at flange.

Resonator (or the shell in the embodiment of Fig. 5 B and Fig. 5 C) is usually stainless, in stainless steel material, sound Speed is about Cstainless steel=5790m/s.

Some black attributes are a quarter (the Cink ≈ 1200m/ making the velocity of wave in ink be the velocity of wave in rustless steel s).As a result, black chamber also constitutes the resonator that wherein can develop standing wave, and the resonance of standing wave and anti-resonance frequency will be close to execute The resonant frequency of device.

Velocity of wave in rustless steel (or more generally, in the material constituting bar) has low-down sensitivity to temperature Property, and the velocity of wave in ink has the very high sensitivity change of -3 and -4m/s (every degree Celsius have) to temperature.For being based on The ink of MEK (butanone) solvent, ethanol or water, be have collected in figure 16 and is changed with function, this speed the time as temperature Become relevant data.In the figure, the data with regard to the velocity of sound in black #1 (its solvent be MEK) and #2 show strong enough Variability.For the black #3 with " water " base, this variability is lower.

The mode of resonance in mode of resonance and chamber in resonator is in close proximity to each other, and the function as temperature and Differently change.Therefore, by the pattern of cross-section (intersect) resonator (pattern of resonator as temperature function and Change is very little), the mode of resonance of fluid cavity and anti-resonance mode can be configured so that the function of temperature.

The first research that this problem is implemented is related to be equipped with the situation of the droplet generator that Fig. 5 D type encourages main body.

In fig. 7, curve I is denoted as function, (Ve is the input voltage of excitation range) Ve time of temperature and changes Become.As can be seen in this curve, in this scope beginning, driving voltage keeps stable, and in other words, it reflects Launching efficiency.On the other hand, this voltage tends to from 25 DEG C scanning temperature dramatically increases from low to high.

In same in figure, curve II be denoted as temperature function, Vs (Vs is the output voltage of excitation range) when Between change.Notice peak value on this curve II at about 25 DEG C.

Curve III is denoted as function, the Vs/Ve of temperature, and (this is the input voltage/output voltage ratio of excitation range Rate) time change.This ratio represents that excitation is strong：Higher it is easier to setting printer, this is because single driving voltage makes Obtain and can run through temperature range formation quality drop.Here, it is noted that from about 25 DEG C, this drift is very high.

Curve IV represents that the time of the voltage at flex point Vr changes.This is initially stable, then, as input electricity Pressure, the increase from about 25 DEG C as the function of temperature.

Function, in rupture length Lb the time being denoted as temperature (from 5 DEG C to 45 DEG C, by 5 DEG C of spacing) changes, And driving voltage can be set.Represent these curves in figure 7b.

According to these curves, attempt determining how launching efficiency changes as the function of temperature.For this reason, in given electricity It appears that rupture length Lb can change according to factor 2 as the function of temperature at pressure.Based on capillary instability reason By acquisition following formula：

Wherein：

Lb：Rupture length

a：Radius of spray from nozzle

Vj：Average jet velocity

ΔVj：Jet velocity modulation (result of excitation process)

γ：The no size rate of rise of modulation, this speed is in the upper substantial constant of opereating specification (especially temperature range)

We：Weber number.

Velocity modulation changes with rupture length index, and therefore encourages change in ratio to be far above factor 2.

Because purpose is that the modulation level under different temperatures is compared, show launching efficiency 20 DEG C and 40 DEG C it Between hugely decline.The impact of temperature can change a few percent of |input paramete (typically, surface tension ...), this with swash The magnitude encouraging size in efficiency is unrelated.

In order to explain this unexpected efficiency change, can attempt：

Non-linear, not yet determine (impossible) so far；

Or resonance phenomena.

Therefore, by searching for resonance in solid and liquid, excitation body can be noticed.

Approximate as first, can reasonably consider the material of resonator, for example, for bar pottery and rustless steel several It is stable in ten degree of scope.The electric charge being returned to executor by ink ribbon will not be so that huge on launching efficiency to be explained changes Become.

In liquid (there is ink Anywhere), once the full-size of liquid is in the magnitude of wavelength, acoustic resonance Phenomenon may exist.

Speed (in the ink based on MEK) in 83kHz and for about 1200m/s, wavelength is typically 15mm, wavelength Shorter, but but in the magnitude of size with excitation main body height be analogous (in the exemplary geometric structure of Fig. 5 D, About 21mm herein).

By including the propagation phenomenon in ink, following relation can be set：This relationship expression is generated by piezo actuator Modulation and jet velocity modulate Δ Vj between dependency.Complete transmission function can be determined, and relevant with ink And the presence of the resonant frequency near operation frequency can be searched.These frequencies (resonance or transmission zero (antiresonance)) and then The Study of Sensitivity of the function as temperature can be subject to.Interested, check these frequencies whether drift about and/or with (by holding Row device is forced) operation frequency intersection.

Droplet generator can schematically be explained to list its main functional component.Fig. 8 (and represent in fig .9 , its equivalent for circuit) show the simplification of droplet generator made by manufacturing obvious four elements Version：

Source item：Piezo actuator, piezo actuator is modulated to black flow rate (it is into intake rate)；

Loss item：These are the outgoing flow rates balancing into intake rate.Here, there are 3 items：Executor 52 lower section Black wedge 520, wherein can be with the nozzle 50 of the excitation main body of conduct acoustic waves and top 550.

Resonator body (being for example, stainless) is considered can not deformation：Wall has zero velocity condition, but regardless of being No flowing or propagate.

The physical behavio(u)r of the function element of droplet generator and equation associated there will be provided now.For this reason, really The impedance of each element fixed.

These pressure drop by nozzle 50 are described by Navier Stokes equation.In sinusoidal model, in spray The movement of the black quality catching in mouth is limited by Inertia.Nozzle impedance will be denoted as Zb：

Wherein：

L nozzle：Nozzle length

Sb：Nozzle area

ρ：Black density

ω:Angular frequency under the operating frequency.

Black wedge 520 under executor be related to the input of nozzle post (this post be located at moveable nozzle plate in But before being connected to the region 521 of nozzle 50) and the ink " disk " below the significant surface of executor.For This post, e.g. 500 μm of diameter, with compared with the nozzle diameter being taken as 50 μm again in an illustrative manner.Therefore, wedge In black speed very low compared to for nozzle (factor 100).Therefore, fluid can be considered motionless (does not have inertia to imitate Should).Therefore, wedge impedance is only its compressibility item, is denoted as Zc：

Wherein, Ke is compressibility, and Ve is the black volume in region 521.

Waveguide 550 is the acoustic element being limited by the significant surface of resonator；It rises to the shoulder 53 of supporting resonator Level.The flowing of this region has liquid, and therefore, Breakup of Liquid Ring is considered between the sheath of resonator and excitation main body.

It should be recalled that liquid column has interval change, the every section of impedance of this post is by lineation opinion (line theory) The formula of (in electric simulation) is given：

Wherein ZBC is the equivalent impedance of the input of the section AB with acoustic impedance Zb being terminated by electric charge impedance Z AB.

Piezo actuator and then have can be by local constant (simulation of quality spring) the resonance behavior that approximately be modeled.Mirror In the impedance relevant with executor with respect to fluid, executor is overriding：In the first rank, the resonance frequency of Drive assembly Rate is arranged to the resonance of 1/2 Langevin (resonator) of in the air.

Because operation frequency is fixing (83.3KHz), for the model of more readability, this mechanical resonant will not be considered. Therefore, resonant component assimilates as flow rate source, and this is the black volume in the agitation of the end of resonator Q.

To limit cell impedance item for outgoing flow rate, it is possible to determining the pressure P of the end of bar.With nozzle resistance Anti- Z_NozzlePressure drop in nozzle of equal value gives the flow rate of the function as frequency, or even gives for giving The interval jet velocity modulation of nozzle.

Formula before has made it possible to be plotted in the curve (Figure 10 A) of the frequency response at a temperature of 5 DEG C, and this curve is Model as the jet velocity modulation of the function of frequency.Speed unit is normalized, and this makes it possible to relatively position enhancing (resonance phenomena) or weaken the frequency that (transmission zero, antiresonance) encourages.

Notice in the figure in frequency range interested, i.e. 80-90KHz, there are two noticeable frequencies F1 and F2, this two frequencies have an impact to the level of efficiency of excitation in 83.3KHz.If these frequencies are in the operation ring of printer It is stable in border, then this frequency overall space will not cause any problem；At most, printer stimulation level each other may not With.

But these frequencies F1, F2 change as the function of temperature, this seemingly upsets the robustness for excitation Parameter.Simulation by the use of " MathCad " software enables the black speed as strong affecting parameters to be determined.In room temperature (ginseng See the tachometric survey in the 71st edition-the 14-32 page of physics handbook 1990-1991-, and the actual ink of the curve of Figure 16), Mo Su Degree is typically in the range of every DEG C from -3 to -4m/s.

As experimentally detected, in 45 DEG C of temperature range, carry out same simulation, this makes it possible to by force Adjust the frequency shift (FS) (Figure 10 B) of F1, F2 of about 10KHz.Instruction (sign) as the speed dependence of the function of temperature is high , this is to slide due to temperature to make frequency F2 pretty troublesome, and F1 deactivates frequency field.

This frequency shift (FS) may seem sufficiently low；However, when combining with F1 and F2 of about 83.3KHz neighbouring, reason Solution to be to be possible to that when F2 is intersected with operation frequency high change is had on stimulation level.

The test of above-reported has made it possible to emphasize acoustic resonance phenomenon in fluid intracavity.This phenomenon depends in ink Sound wave spread speed；Dependency as the function of temperature therefore occurs, this by the state event location in frequency closer to Or less close to operation frequency.

Using same type of excitation tuning, have been made by supplementary result (actual measurement).These measurements are using following Arrange and achieve and simulation situation identical excitation main body before：The result that figure 11 illustrates.

For these measurements, using low-voltage (low excitation), have been made by frequency in different temperature (5 DEG C -45 DEG C) The measurement of the rupture length Lb during rate scanning, to observe the event in 70-100KHz scope.Measure rupture length Lb. These measurements are to make in the temperature range from 5 DEG C to 45 DEG C, and wherein spacing is 10 DEG C, employs following parameter：

The ink of antholeucin MEK base,

Jet velocity：20m/s,

The pumping signal (50% duty factor) being generated by laboratory installation,

Pattern field main body (there is the structure of Fig. 5 D) equipped with piezo actuator, the resonant frequency of piezo actuator Close to operation frequency (operation frequency is drop formation frequency).

The result that figure 11 illustrates shows the many events with regard to operation frequency 83.3KHz.These curves are as temperature The function of degree and intersect, and the bare minimum of rupture length significantly drifts about as the function of temperature.This operation makes excitation Robustness deteriorates.

These supplement the upset reported above observed by results verification.On the other hand, they show Temperature below maintains the difficulty of stable operation or or even the impossibility of droplet generating apparatus：At least two away from about 15 DEG C Or 20 DEG C of positive temperature, such as on the one hand away from 5 DEG C and/or 15 DEG C, on the other hand away from 30 DEG C and/or 35 DEG C and/or 45 DEG C, On the other hand more generally in scope with aspect from 5 DEG C or 15 DEG C to 35 DEG C or 45 DEG C or even 50 DEG C of temperature range.

Other work have had been acknowledged the hypothesis of the impact of the upset relevant with resonance present in fluid cavity.To tool The droplet generator having printhead G has made actual measurement, and (therefore, chamber resonator is cylindrical to the mechanical simplicity of printhead G , it is as the type in Fig. 5 A) make it possible to more easily calculate the resonance behavior of fluid cavity.

The excitation main body therefore having been directed towards that type of Fig. 5 A implements supplementary test.

More accurately, have been directed towards the rupture length that three temperature have investigated the function as frequency using low excitation.Due to Driving voltage is 7 volts, and it makes it possible to there is " slow " satellite all the time, and the linear reason therefore according to capillary instability By rupture length is directly related with launching efficiency.

The temperature tested is 5 DEG C, 25 DEG C and 45 DEG C.

The ink being used is pressurization whiteness MEK base ink to reach the constant jet velocity of 20m/s.In constant ripple Test has been made under length；Therefore, readjust jet velocity not as the function of frequency, and obtain parabolic type shell, this Reflect physics capillary instability phenomenon, this phenomenon will be considered when with result.

It has been shown that the resonance in the point of measurement of Lb and chamber and anti-resonance frequency, chamber in Figure 12 A-C In resonance and anti-resonance frequency be numerically mechanical arrangements according to generator and at different temperatures the velocity of sound in ink and Calculate.Transmission zero (antiresonance) to be determined by vertical bar.Peak Pc (Figure 12 A and B) or PC1, PC2 (Figure 12 C) represent liquid In resonance peak.

For 5 DEG C (Figure 12 A)：

Have adjusted theoretical model using speed c=1170m/s in ink.The resonant frequency of executor is about 64KHz.This model furthermore present two transmission zero corresponding to 46kHz and 74kHz.For 46kHz, associated efficiency Reduction is again found to；But, for 74kHz it is impossible to read these values, this is because this rupture is in making an uproar of Natural Ruptures In sound.

This model has also predicted the resonance peak at about 57kHz significantly observed on the curve of rupture length Value.Further highlights the resonance phenomena at 64kHz, for amplitude, it is dominant, this is because it is to be forced by executor 's.

For 25 DEG C (Figure 12 B)：

Have adjusted this theoretical model by the use of the c=1100m/s of the slope as -3.5m/s/ DEG C.Two transmission zero It is respectively positioned on about 42kHz and 69kHz.This is identified well by following experimental data：This experimental data is at these frequencies Lead to the sub- efficiency (sub-efficiency) encouraging.Also the acoustic resonance in black chamber is highlighted well at about 53KHz.? See executor's resonance well, but lack of resolution is broken so that this that be likely to be between 63kHz and 64kHz is precisely located Split length minima.

For 50 DEG C (Figure 12 C)

The c=1030m/s that make use of the slope as -3.5m/s/ DEG C have adjusted theoretical model.First zero quilt Be found in 40kHz slightly before, and second zero is found in 65kHz.The latter is in close proximity to operation frequency and therefore becomes Become to be superimposed with the resonance peak of the executor at 64kHz.

In order to solve the exception observed above it is proposed that adjusting the acoustic impedance near nozzle 10 of this system, more The acoustic impedance of body ground fluid cavity.

This acoustic impedance changes as the function of frequency, especially when this changes around operation frequency.

In figure 13a, illustrate as the function of frequency and be directed to given temperature, the typical case in this acoustic impedance Time changes (near nozzle 10 or at nozzle 10).Operation frequency (in other words, the operation frequency of chamber and executor of system Rate) to be identified by ft, and value under this operation frequency for the described acoustic impedance is designated as ZT (ft).Feelings in Fig. 5 A-5D Under condition, this operation frequency to limit by resonator with by chamber.In the case of Fig. 5 E, by the geometry knot of rustless steel cylinder 32 Structure is limiting operation frequency.

As seen in figure 13a, acoustic impedance is equably or smoothly varying around ft.But, explain when above When the upset of the type stated occurs, in the plot, especially near operation frequency, for example, around operation frequency+ In the interval of 10kHz or+5kHz, one or more peak value P1, P2 of resonance or antiresonance occur.

This impedance variation result in the amplitude of jet velocity modulation (or even launching efficiency) in nozzle and therefore Rupture length change.

Further, the curve chart of Figure 13 A changes as the function of temperature.In certain temperature for example at 5 DEG C or 15 DEG C, the peak value of such as peak value p1, p2 that is not present in searched for frequency interval can occur in same frequency interval another One temperature is for example at 30 DEG C or at 35 DEG C.

According to the present invention, limit the frequency range [f1, the f2] of+10kHz or+5KHz around operation frequency ft.This system For making when frequency changes in this range, the value of the velocity modulation in nozzle at temperature T with respect to 25 DEG C in nozzle Velocity modulation following interval outside do not change：This interval is between 0.25 (or 0.5) and 2 (or even 4)；Temperature T For 15 DEG C and 35 DEG C, preferably also it is 5 DEG C and/or 10 DEG C and/or 20 DEG C, be also further preferably 45 DEG C or even 50 DEG C, it is further preferably (or to 40 DEG C or to 45 DEG C or to 50 between at least 15 DEG C (or 10 DEG C or 5 DEG C) Dao at least 35 DEG C DEG C) temperature range in included any temperature.The example at this interval of velocity modulation carrys out table by the horizontal beam in Figure 13 B Show.Therefore, it is to avoid：

On the one hand, the depositing in the interval close to ft of the peak value (P ' 1 in such as Figure 13 B and P ' 2) that reflection is upset ?；

On the other hand, as the drift arriving ft in function, such peak value of temperature.

It is noted that can be according to formula computing impedance already mentioned above.According to this calculating, jet velocity modulation and its Change under the influence of the temperature can be inferred.

Therefore, the Lb (in addition having provided its formula above) in constant excitation voltage, according to the function as frequency On change measurement, can estimate or be inferred to this velocity modulation.In fact, the change on Lb reflects the change in impedance Change.

Alternatively it is possible to measurement or estimate as the change on function the, pressure of frequency.At nozzle 10, pressure These changes in power represent or reflect the change on Lb and the change on acoustic impedance (that is, jet velocity modulation).

Solution provided above can be intended to by modification receive the configuration of the internal capacity of excitation main body of ink To realize, to give its shape and enable to make the change on acoustic impedance.

In other words, internal at least one Part I easily including there is the first acoustic impedance and having different from the At least one Part II of second acoustic impedance of one acoustic impedance.

For example, in chamber, an element or device can be introduced, enable to make this change in impedance.This solution Certainly the embodiment of scheme is shown in Figure 14 A-14E.

The equipment (respectively Figure 14 B, Figure 14 C, Figure 14 D, Figure 14 E) of Figure 14 A correspond to Fig. 5 A (respectively Fig. 5 B, Fig. 5 C, Fig. 5 D, Fig. 5 E) equipment, identical reference number refers to identical element.Each in figure in these Figure 14, the ring of annular 27th, 37,47,57 have been incorporated in the internal capacity in chamber.The overall diameter of this ring is substantially equal to the interior of shell 25,32,42 Diameter, and its inside diameter will not hinder flow of fluid.Material for this ring is preferably identical with the material of resonator, example As rustless steel.

In these figures, ring be shown in chamber lower partly in.Alternatively, ring can be placed in another part, For example, according to the arrangement representing in the dotted line on each figure of these figures.Thus, ring can have chamber acoustic impedance is carried out The same effect of modification.

More generally it is also noted that, on these figures, the interior shape in chamber includes：

First cylindrical region 251 of the first diameter and along described chamber the first length of longitudinal axis measurement, 321,421, 521st, 621,

Second cylinder of Second bobbin diameter and along described chamber second length of longitudinal axis measurement different from the first diameter Region 252,322,422,522,622.

In the case of the ring of each figure positioning Figure 14 in the position according to indicated by dotted line, the first cylindrical region and Two cylindrical regions are different from those discussed above cylindrical region.

As will be shown below, in acoustic impedance in the example of Figure 14, being caused by the different-diameter in chamber Difference or change make it possible to remove from the region of operation frequency by resonance institute unique for accommodating the chamber of liquid The undesire frequency leading to, and hence in so that being capable of stabilized speed modulation.

Different diameters makes it possible to make the change in fluid length.In the case of the structure of Figure 14 A and Figure 14 D (wherein, resonator is dipped in the chamber being intended to accommodate fluid), create mechanical actuator (include piezoelectric element 21,51, flange 23rd, 53 and the part 22,52 that contacts with fluid) length La and this part being intended to the chamber accommodating fluid column or a part Ratio between length Lf；This ratio can for example be included between 4 and 6 or 4 and 10 or 100.In the case of Figure 14 D, The length of the part of region B that length Lf does not occupy corresponding to ring 57.If even if (its length is not by the presence institute of ring for fluid column Modification) it is left it is intended to the modulation in the length of the part in the chamber accommodating fluid makes it possible to from the region of operation frequency Remove undesire frequency.

Using the structure of the excitation main body of Figure 14 D, using length, in last investigation, the ring for 3.6mm is made Test.Show result in Figure 15 A-15C：

The time that Figure 15 A is denoted as on function, voltage Ve, Vs, Vr and ratio Vs/Ve of temperature changes；This figure 15A shows the nonlinear change existing on piezoelectricity set-point.Accordingly, it is appreciated that the result by it and with reference to Fig. 7 A discussion for the ground Compare；

Figure 15 B represents in different temperatures (5 DEG C -45 DEG C, spacing is 10 DEG C, at 5 DEG C, 15 DEG C, 25 DEG C, 35 DEG C, 45 DEG C) Rupture length Lb as the function of activation voltage；It is noted that these curves have suitably been stacked with correct order；Again, With the curve of Fig. 7 B be relatively very favorable,

Figure 15 C represents in different temperature (5 DEG C -45 DEG C, spacing is 10 DEG C, at 5 DEG C, 15 DEG C, 25 DEG C, 35 DEG C, 45 DEG C) The function as frequency rupture length Lb；Suitably stack these curves as the function of temperature, with correct order, And these curves mutually disjoint.This result than in Figure 11 observe result much higher, in fig. 11, be sequentially mistake simultaneously And curve intersects each other.

Utilize " the MEK yl of standard " type ink and and then make supplementary test using " alcohol-based " type ink. The result being obtained similar to first two ink, and confirm the optkmal characteristics of 3.6mm ring.

The presence of ring enables the volume in black chamber to reduce, and this is conducive to the clear of during attended operation droplet generator Wash.

Test above shows the invention allows to (Negotiation speed) runs through considered temperature and black scope is real Existing strong operation.The invention allows to any upset event on removal launching efficiency.In the most number curve being obtained On notice and be markedly improved, i.e. random operation is switched to the operation of good control.

The embodiments of the invention wherein inserting the ring in the chamber of modulation main body can be by direct Processing farage main body Ring function substituted, therefore, modulation main body become single-piece and modulate the change that main body has on area of section, therefore have With the represented same or similar profile of profile in Figure 14 A-14E.

According to another embodiment, detect the difference on the SVEL in various materials than stainless steel.So Resonator with having one of these other materials substitutes used rustless steel afterwards.

This solution enables the condition providing above in conjunction with Figure 13 B to be satisfied.

This solution also enables to change resonator length while keeping same operation frequency.Using resonator Modification in length completes the selection of another material, and wherein resonator length is proportional to speed ratio first.

If speed is more than the speed in rustless steel, bar below the flange of resonator (Fig. 5 A and Fig. 5 D or Figure 14 A and The situation of Figure 14 D) will be expanded；If on the contrary, speed is lower, the bar below flange will be shortened.Therefore, it can for example by According to the length changing the resonator cavity accommodating fluid according to the teaching before invention：

In the frequency range of+5KHz around operation frequency ft, there is under the operation frequency in executor and chamber value Δ Vj (ft) from nozzle jet velocity modulation and 15 DEG C of temperature and 35 DEG C of temperature this jet velocity modulation do not exist Change outside interval between 0.25 Δ Vj (ft) and 4 Δ Vj (ft)；

And/or between mechanical actuator length and this part in chamber or the length of a part that are intended to receiving fluid column Ratio strictly be higher than 4；This ratio can be for example between 4 and 6 or between 4 and 10 or 100.

In this case, the resonance of fluid cavity and anti-resonance frequency by displacement or are refused outside excitation operating area.

Form I have collected the data relevant with the SVEL in these other materials.

Form I

The upset effect of the sound wave in ink if one of these other materials are preserved for resonator rod, will not be assumed Should.

More generally, whole metal materials than stainless steel or mineral material can also be suitable.

This selection is further such that the length of resonator may can be reduced and therefore, it is possible to reduce cavity length, this more enters One step ground makes it possible to avoid spurious resonance as explained above.

No matter the structure of excitation main body is the structure of excitation main body of Fig. 5 A-5D or the excitation main body of Figure 14 A-14D Structure, the upset effect being led to due to the resonance accommodating in black chamber will not occur.

Have and realized according to equipment, the method for dripping to formation black liquid of one of the embodiment refining above Ink-jet apparatus or printer are already in connection with the type described by Fig. 1 and Fig. 2.

Therefore, such equipment includes：

Droplet generator 60, droplet generator 60 accommodates and keeps conductive ink under stress by line of ink marker road, and launch to A few ink-jet,

For the charging electrode 64 of each ink-jet, electrode has the gap that injection is passed through.

Assembly, assembly includes two deflecting plates 65 being placed on the either side of injection path and the upstream of charging electrode,

Groove 62, groove 62 is used for reclaiming the ink of the injection not being used for printing so that ink is put back into line of ink marker road and therefore It is recycled.

Describe the operation of this injection types already in connection with Fig. 1 and Fig. 2.Here will be briefly mentioned in droplet generator The ink accommodating is fled from from least one measurement nozzle 10, therefore forms at least one ink-jet.Cycle in the placed upstream of nozzle Property excitation set (not shown) (for example, periodic excitation equipment include in ink place piezoelectric ceramics) in the presence of, ink-jet Rupture the accurate location of the injection upstream in nozzle with regular time interval corresponding with the cycle of pumping signal.Generally by swashing The periodic vibration encouraging equipment causes this compulsory division of ink-jet at so-called " rupture " point 13 of injection.

In addition to devices above, such equipment may further include for each device in these devices The device 5 that the voltage individually operating and being applied is controlled and adjusts.With reference to Figure 17, these are more accurately described Device 5.

In the figure, the assembly of control device 5 includes following circuit, and this circuit makes the electricity for driving printhead Pressure and the voltage of electrode especially to be applied to and latter voltage can be sent to printhead.

This assembly 5 can receive downstream signal from printhead further, especially with position and/or liquid drop speed sensing The signal of device measurement, and these signals can be processed and be used for controlling printhead and line of ink marker road by these signals. Especially, in order to process the signal from such sensor, assembly 5 can include following device：For to from this sensing This signal of device is simulated the device that ground amplifies, for being digitized to this signal (translating the signals into as a column of figure sample This A/D conversion) device, for signal is carried out noise reduction device (for example, for sample one or more numeral filter Ripple device), for searching for the device of the maximum (maximum of this row sample) of signal.

This controller assemblies 5 can with for fluid is sent to the device that printhead/be used for receives fluid from printhead 500 communications.

Controller assemblies 5 can communicate with to inform the user printer modes and performed measurement with user interface 6, especially It is the type of those described below.Controller assemblies 5 include the storage dress for storing the instruction relevant with data processing Put, such as to execute the algorithm of method described above or execution type described above.

According to exemplary embodiment, controller 5 includes embedded CPU, and CPU itself includes micro- Processor, one group of nonvolatile memory and RAM, peripheral circuit, all these elements be all coupled to bus.Data can be deposited Store up in memory area, in particular for realizing the data of the method according to the invention or being used for the equipment according to the present invention is entered The data that row controls.

Device 6 allows users to interact with the printer according to the present invention by following operation：For example, beaten by execution Print machine configuration with operate debugging arrive production line requirement (ratio, print speed ...) and more generally its environment, And/or the printing content made in the preparation of production phase for determination, product especially on a production line, and/or logical After showing the information for the follow-up things the producing quantity ... of the product being tagged (state of consumer goodss) in real time. These devices 6 can include viewing apparatus.

Can further provide for for expecting voltage or the device by electrode band to expectation voltage to electrode supply.These dresses Put and especially include voltage source.

Printer (its behaviour already mentioned above that is described above, being applied to type with reference to Fig. 1 and Fig. 2 description Make), the excitation main body according to the present invention and be used for make it possible to according to the method that the excitation main body of the present invention is operated Make strong excitation, this will not have with reference to known device to introduce during the application shown go out problem.Especially, this swashs It is more stable for encouraging in following temperature：Away from least 15 DEG C or more at least two temperature, especially 15 DEG C and 30 DEG C (or 35 DEG C) it is preferable that also at 5 DEG C and/or 10 DEG C and/or 20 DEG C, further preferably 40 DEG C or 45 DEG C or even 50 DEG C, Further preferably in the scope between 15 DEG C and 35 DEG C and more generally any in the scope between 5 DEG C and 50 DEG C Temperature.

Using apparatus and method according to the invention, from the operational frequency range being used, abandon " parasitic " frequency, and Regardless of the temperature in any scope discussed above.For example, selected diameter and jet velocity are depended on, this operation Scope is between 50KHz and 150KHz.

Claims (20)

1. a kind of for formed and launch continuous inkjet printers device ink-jet drop equipment, this equipment includes：

A) chamber (25,32,42), described chamber is used for accommodating ink and including being equipped with the end of nozzle (10), and described nozzle is used Drip in ejection black liquid,

B) actuator apparatus (21,22,32,41,42), described actuator apparatus are contacted with described chamber,

In the apparatus, under the operation frequency of described chamber and described executor, from the jet velocity of described nozzle (10) Modulation has value Δ Vj (f_t), and the temperature at 15 DEG C and at a temperature of 35 DEG C, around operation frequency f_t± 5kHz In frequency range, this jet velocity is modulated not in 0.25 Δ Vj (f_t) and 4 Δ Vj (f_t) between scope outside change.

2. equipment according to claim 1, wherein, equally at a temperature of 5 DEG C and 45 DEG C and/or 50 DEG C, around institute State operation frequency f_tThe frequency range of ± 5kHz in, the described jet velocity from described nozzle (10) is modulated not in scope 0.25ΔVj(f_t) and 4 Δ Vj (f_t) outside change.

3. equipment according to claim 1 and 2, wherein, the internal capacity of ink chamber includes thering is the first acoustic resistance extremely A few Part I and at least one Part II with the second acoustic resistance different from the first acoustic resistance.

4. the equipment according to one of claims 1 to 3, the interior shape in described chamber includes：

- the first cylindrical region (25₁, 32₁, 42₁, 52₁, 62₁), described first cylindrical region has the first diameter and along described chamber Longitudinal axis measurement the first length,

- the second cylindrical region (25₂, 32₂, 42₂, 52₂, 62₂), described second cylindrical region has different from described first diameter Second bobbin diameter and the second length of the longitudinal axis measurement along described chamber.

5. equipment according to claim 4, the described chamber with cylindrical interior shape has equal to described first diameter Diameter, and described chamber is equipped with cylinder ring (27,37,47), and the inside diameter of described cylinder ring is equal to described Second bobbin diameter.

6. equipment according to claim 4, described chamber is by having the first column part and have the second column part Wall limits, and described first column part has the inside diameter equal to described first diameter, the inside of described second column part Diameter is equal to described Second bobbin diameter.

7. the equipment according to one of claim 1 to 6, described Resonator device includes piezoelectric element (21,31,41).

8. the internal capacity directly contact in the equipment according to one of claim 1 to 7, described executor and described chamber.

9. the equipment according to one of claim 1 to 7, described executor includes Resonator device.

10. equipment according to claim 9, described Resonator device includes the resonator body being arranged in described chamber (22,52).

11. equipment according to claim 10, described resonator body (22,52) be rustless steel, aluminum, beryllium, pyrite, copper, Diamond, glass, gold, ferrum, lead, TMMA, silver or titanium.

12. equipment according to claim 10 or 11, described resonator body (52) includes thering is the first of the first diameter Partly (52₁) and there is the Part II (52 of the Second bobbin diameter different from described first diameter₂).

13. equipment according to claim 9, the internal capacity in described chamber to be limited by resonator walls (32,42).

14. a kind of for formed and launch continuous inkjet printers device ink-jet drop equipment, this equipment includes：

A) chamber, described chamber is used for accommodating ink and includes being equipped with the end of nozzle, and described nozzle is used for launching black liquid and drips,

B) actuator apparatus (21,22,32,41,42), described actuator apparatus are contacted with described chamber, described actuator apparatus Material is selected from aluminum, beryllium, pyrite, copper, diamond, glass, gold, ferrum, lead, TMMA, silver or titanium.

15. equipment according to claim 14, described Resonator device includes piezoelectric element (21,31,41).

16. equipment according to one of claim 14 and 15, described Resonator device includes being arranged on humorous in described chamber Device main body of shaking (22,52).

17. equipment according to claim 16, described resonator body (52) includes the Part I with the first diameter (52₁) and there is the Part II (52 of the Second bobbin diameter different from described first diameter₂).

18. equipment according to one of claim 14 and 15, the internal capacity in described chamber to be limited by resonator walls (32,42) Fixed.

A kind of 19. continuous inkjet type printer devices, this machine includes：

- printhead (1), described printhead be equipped with according to one of claim 1 to 18 for being formed and launching The equipment of the drop of ink-jet,

- line of ink marker road (4),

- for the device (5) that black circulation and described printhead are controlled.

20. a kind of for forming the method that black liquid is dripped, wherein, realize equipment according to one of claim 1 to 18 or root According to the machine described in claim 19.